/*
 * This file is part of the Flowee project
 * Copyright (C) 2024-2025 Tom Zander <tom@flowee.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "QMLTransferManager.h"
#include "FloweePay.h"
#include "TxInfoObject.h"

#include <QFile>
#include <QTimer>
#include <TransactionBuilder.h>


QMLTransferManager::QMLTransferManager(QObject *parent)
    : QObject(parent)
{
}

void QMLTransferManager::prepare()
{
    if (m_prepareRunning)
        return;
    assert(m_fromAccount);
    m_prepareRunning = true;
    freePreparedTransactions(); // also clears the transactions list.

    // the following may take a bit longer if the wallet is large.
    // do this a tad later in order to avoid the button press not
    // seeming to do anything.
    const auto wIn = m_fromAccount->wallet();

    if (m_fromAccount->isSingleAddressAccount()) {
        // We create one transaction per UTXO, since the alternative
        // is one big transaction for this kind of wallet.
        QTimer::singleShot(100, this, [=]() {
            const auto walletSecrets = wIn->walletSecrets();
            assert(walletSecrets.size() == 1);
            auto secret = walletSecrets.begin();
            const auto utxos = wIn->unspentOutputsForKey(secret->first);
            for (const auto &utxo : utxos) {
                // NOTICE in future we may want to support token moving as well.
                if (wIn->txOutput(utxo).hasCashToken == false) {
                    PreviewTx *tx = new PreviewTx(this);
                    tx->m_utxos.push_back(utxo);
                    tx->m_value += wIn->utxoOutputValue(utxo);
                    const auto &fromSecret = secret->second;
                    tx->m_from = new Address(renderAddress(fromSecret.address),
                            fromSecret.cloakedAddress(), tx);
                    m_transactions.append(tx);
                }
            }
            emit transactionsChanged();
            emit unsentTxCountChanged();
            m_prepareRunning = false;
        });

        return;
    }

    QTimer::singleShot(100, this, [=]() {
        // we create one transaction for each address (aka private key).
        // Regardless how many inputs this creates in a transaction.
        const auto walletSecrets = wIn->walletSecrets();
        for (auto i = walletSecrets.begin(); i != walletSecrets.end(); ++i) {
            const auto utxos = wIn->unspentOutputsForKey(i->first);
            bool foundOne = false;
            for (const auto &utxo : utxos) {
                // NOTICE in future we may want to support token moving as well.
                if (wIn->txOutput(utxo).hasCashToken == false) {
                    foundOne = true;
                    break;
                }
            }

            if (foundOne) {
                PreviewTx *tx = new PreviewTx(this);
                tx->m_utxos = utxos;
                for (const auto &utxo : utxos) {
                    tx->m_value += wIn->utxoOutputValue(utxo);
                }
                const auto &fromSecret = i->second;
                tx->m_from = new Address(renderAddress(fromSecret.address),
                        fromSecret.cloakedAddress(), tx);
                m_transactions.append(tx);
            }
        }

        emit transactionsChanged();
        emit unsentTxCountChanged();
        m_prepareRunning = false;
    });
}

void QMLTransferManager::send(QObject *previewTx)
{
    assert(previewTx);
    auto data = qobject_cast<PreviewTx*>(previewTx);
    if (!data)
        return;
    if (data->m_sent)
        return;
    // create the actual minable transaction
    Tx tx;
    try {
        tx = createTx(data);
    } catch (const std::exception &e) {
        logCritical(10053) << e;
        return;
    }
    data->m_sent = true;

    // call to fromWallet to mark outputs locked and save tx.
    auto fromWallet = m_fromAccount->wallet();
    fromWallet->addTransaction(tx, Wallet::NoNotification);
    fromWallet->setTransactionComment(tx, tr("Migrated Coin"));
    // call to toWallet to have it too!
    auto toWallet = m_toAccount->wallet();
    toWallet->addTransaction(tx, Wallet::NoNotification);
    toWallet->setTransactionComment(tx, tr("Migrated Coin"));
    // and broadcast it.
    auto txInfo = std::make_shared<TxInfoObject>(m_toAccount->wallet(), tx);
    FloweePay::instance()->broadcastTransaction(txInfo);
    // the txInfo is a sharedPtr, we need to store it somewhere to not get deleted
    // when it goes out of scope at the end of this method.
    data->setFinalTx(txInfo);
    emit data->sentChanged();
    emit unsentTxCountChanged();
}

void QMLTransferManager::sendAll()
{
    assert(m_fromAccount);
    assert(m_toAccount);
    for (auto data_ : std::as_const(m_transactions)) {
        auto *data = qobject_cast<PreviewTx*>(data_);
        send(data);
    }
    emit unsentTxCountChanged();
}

int QMLTransferManager::coinCount() const
{
    return m_coinCount;
}

int QMLTransferManager::unsentTxCount() const
{
    int count = 0;
    for (auto *tx_ : m_transactions) {
        auto *tx = qobject_cast<PreviewTx*>(tx_);
        if (!tx->m_sent)
            ++count;
    }
    return count;
}

bool QMLTransferManager::inputsOk() const
{
    if (m_fromAccount == nullptr)
        return false;
    if (m_addressCount == 0)
        return false;
    if (!m_fromAccount->isDecrypted())
        return false;
    if (m_toAccount == nullptr)
        return false;
    if (m_toAccount->needsPinToOpen() && !m_toAccount->isDecrypted())
        return false;
    if (m_toAccount->isSingleAddressAccount())
        return false;
    return m_toAccount != m_fromAccount;
}

void QMLTransferManager::setCoinCount(int c)
{
    if (m_coinCount == c)
        return;
    m_coinCount = c;
    emit coinCountChanged();
}

void QMLTransferManager::freePreparedTransactions()
{
    if (!m_transactions.isEmpty()) {
        qDeleteAll(m_transactions);
        m_transactions.clear();
        emit transactionsChanged();
    }
}

Tx QMLTransferManager::createTx(PreviewTx *tx)
{
    assert(tx);
    assert(!tx->m_sent);
    assert(m_fromAccount);
    assert(m_toAccount);
    assert(tx->outputCount() >= 1);
    assert(tx->outputCount() <= 400);
    const auto wIn = m_fromAccount->wallet();
    assert(wIn);
    auto wTo = m_toAccount->wallet();
    assert(wTo);

    TransactionBuilder builder;
    builder.setFeeTarget(1000);
    builder.setAnonimize(true);
    uint64_t value = 0;
    for (auto ref : tx->m_utxos) {
        auto output = wIn->txOutput(ref);
        if (output.hasCashToken)
            continue;
        value += output.outputValue;
        builder.appendInput(wIn->txid(ref), ref.outputIndex());
        auto priv = wIn->unlockKey(ref);
        if (priv.sigType == Wallet::NotUsedYet)
            priv.sigType = Wallet::SignedAsSchnorr;
        TransactionBuilder::SignatureType typeToUse =
                (priv.sigType == Wallet::SignedAsEcdsa) ? TransactionBuilder::ECDSA : TransactionBuilder::Schnorr;
        assert(priv.key.isValid());
        builder.pushInputSignature(priv.key, output.outputScript, output.outputValue, typeToUse);
    }

    uint64_t perOutput = value / tx->outputCount();
    if (perOutput < 700)
        throw std::runtime_error("Too low");
    for (int i = 0; i < tx->outputCount(); ++i) {
        // diff is a fun thing.
        // The idea is to make each output have a slightly random different amount.
        // The anonimize feature of the builder will then sort them based on amount,
        // and this will effectively randomize the outputs ordering.
        // This avoids a large number of addresses being in perfect order on-chain for forever,
        // just in case someday in the future someone can reverse engineer a HD seed from that.
        uint32_t diff = std::rand() % 15;
        builder.appendOutput(perOutput - diff);
        KeyId targetAddress;
        wTo->reserveUnusedAddress(targetAddress, Wallet::ChangePath);
        builder.pushOutputPay2Address(targetAddress);
        builder.setOutputFeeSource(0);
    }

    return builder.createTransaction();
}

QList<QObject *> QMLTransferManager::transactions() const
{
    return m_transactions;
}

NumberModel *QMLTransferManager::outputModel()
{
    if (m_model == nullptr)
        m_model = new NumberModel(this);
    return m_model;
}

int QMLTransferManager::addressCount() const
{
    return m_addressCount;
}

void QMLTransferManager::setAddressCount(int c)
{
    if (m_addressCount == c)
        return;
    m_addressCount = c;
    emit addressCountChanged();
}

AccountInfo *QMLTransferManager::toAccount() const
{
    return m_toAccount;
}

void QMLTransferManager::setToAccount(AccountInfo *newToAccount)
{
    if (m_toAccount == newToAccount)
        return;
    freePreparedTransactions();
    m_toAccount = newToAccount;
    emit toAccountChanged();
    emit inputsOkChanged();
}

AccountInfo *QMLTransferManager::fromAccount() const
{
    return m_fromAccount;
}

void QMLTransferManager::setFromAccount(AccountInfo *account)
{
    if (m_fromAccount == account)
        return;
    m_fromAccount = account;
    emit fromAccountChanged();
    freePreparedTransactions();
    int addresses = 0;
    int totalCoins = 0;
    if (account->wallet()) {
        const auto &wallet = account->wallet();
        if (!account->needsPinToOpen() || account->isDecrypted()) {
            const auto walletSecrets = wallet->walletSecrets();
            for (auto i = walletSecrets.begin(); i != walletSecrets.end(); ++i) {
                auto details = wallet->fetchKeyDetails(i->first);
                if (details.coins > 0) {
                    ++addresses;
                    totalCoins += details.coins;
                }
            }
        }
    }
    setAddressCount(addresses);
    setCoinCount(totalCoins);
    emit inputsOkChanged();
}


// -----------------------------------------------------------

Address::Address(const QString &address, const QString &cloaked, QObject *parent)
    : QObject(parent),
    m_address(address),
    m_cloaked(cloaked)
{
}

QString Address::address() const
{
    return m_address;
}

QString Address::cloakedAddress() const
{
    return m_cloaked;
}


// -----------------------------------------------------------

PreviewTx::PreviewTx(QObject *parent)
    : QObject(parent)
{
}

int64_t PreviewTx::value() const
{
    return m_value;
}

QObject *PreviewTx::from() const
{
    return m_from;
}

int PreviewTx::inputCount() const
{
    return m_utxos.size();
}

void PreviewTx::setFinalTx(const std::shared_ptr<TxInfoObject> &finalTx)
{
    assert(m_finalTx.get() == nullptr); // avoid bugs with connects and only allow this once
    m_finalTx = finalTx;
    if (m_finalTx) {
        connect (m_finalTx.get(), SIGNAL(broadcastStatusChanged()),
                this, SIGNAL(broadcastStatusChanged()));
    }
}

FloweePay::BroadcastStatus PreviewTx::broadcastStatus() const
{
    if (m_finalTx)
        return m_finalTx->broadcastStatus();
    return FloweePay::NotStarted;
}

int PreviewTx::outputCount() const
{
    return m_outputCount;
}

void PreviewTx::setOutputCount(int c)
{
    if (m_outputCount == c)
        return;
    m_outputCount = c;
    emit outputCountChanged();
}

bool PreviewTx::sent() const
{
    return m_sent;
}